draw a line to where the area approach?

I want to draw a line to where the area is approaching. How should i do it?

% excersice 1:
clear all
a = 1
area = 0
figure;
hold on
for i = 1:20
    a = a + a
    area = area + (a *(1/8).^i)
    scatter(i,area)
end
ylabel("value of series")
xlabel("n")

Answer 1

[Image Analyst]

You can use yline() if you have a fairly recent version of MATLAB:

% Exercise 1:
clear all
fontSize = 18;
a = 1
area = 0
figure;
hold on
for k = 1:20
    a = a + a
    area = area + (a *(1/8) .^ k)
    plot(k, area, '.', 'MarkerSize', 40)
end
caption = sprintf('Final value at %.4f', area);
title(caption, 'FontSize', fontSize)
ylabel("value of series", 'FontSize', fontSize)
xlabel("n", 'FontSize', fontSize)
grid on;
yline(area, 'LineWidth', 2, 'Color', 'r');

[Khang Nguyen]

what does yline do?

Answer 2

[KSSV]

a = 1 ;
i = 1:20 ;
area = zeros(size(i)) ; 
for i = 1:20
    a = a + a ; 
    area(i) = (a *(1/8).^i) ;
end
i = 1:20 ;

plot(i,cumsum(area))
ylabel("value of series")
xlabel("n")